Projectiles having a drive cage are known, in which a subcaliber projectile is covered by a bottom and a guide-and centering cap made of plastic, the latter being joined to the former by means of a screw thread, the drive cage serving to accelerate the covered projectile.
During the supply of shells using a drive cage to an automatically fired weapon the drive-cage parts are subjected to a stress in an axial direction, the shell reaching velocities of up to 20 meters/second, being suddenly arrested on impact with the shell chamber. The resulting inertial forces of a heavy shell or projectile act in the direction of firing stress particularly on the joint between the metallic bottom and the guide and centering hood. This leads to a rupture of the assembly at the weakest part of its cross-section, i.e. at the joint of the plastic cap with the bottom, particularly during temperature extremes, even in the case of very strong synthetic resin materials.
Axial locking arrangements have already been proposed (see German published application or Offenlegungsschrift No. 2 007 822) to avoid these disadvantages; these arrangements provide for a locking of the projectile to the bottom of the driving cage until it is fired, the resulting lock being broken by the centrifugal force generated during the spin of the projectile in the barrel. Projectiles of this type suffer, however, from uncontrollable errors, due partly to a relatively clumsy mounting procedure, and partly to a lack of reliability of the locking means which can jam during firing.